1 files changed, 53 insertions, 0 deletions
diff --git a/test/profile/instrprof-merging.cpp b/test/profile/instrprof-merging.cpp
new file mode 100644
index 000000000000..06f05ce612aa
--- /dev/null
+++ b/test/profile/instrprof-merging.cpp
@@ -0,0 +1,53 @@
+// 1) Compile shared code into different object files and into an executable.
+
+// RUN: %clangxx_profgen -fcoverage-mapping %s -c -o %t.v1.o -D_VERSION_1
+// RUN: %clangxx_profgen -fcoverage-mapping %s -c -o %t.v2.o -D_VERSION_2
+// RUN: %clangxx_profgen -fcoverage-mapping %t.v1.o %t.v2.o -o %t.exe
+
+// 2) Collect profile data.
+
+// RUN: env LLVM_PROFILE_FILE=%t.profraw %run %t.exe
+// RUN: llvm-profdata merge %t.profraw -o %t.profdata
+
+// 3) Generate coverage reports from the different object files and the exe.
+
+// RUN: llvm-cov show %t.v1.o -instr-profile=%t.profdata | FileCheck %s -check-prefixes=V1,V1-ONLY
+// RUN: llvm-cov show %t.v2.o -instr-profile=%t.profdata | FileCheck %s -check-prefixes=V2,V2-ONLY
+// RUN: llvm-cov show %t.v1.o -object %t.v2.o -instr-profile=%t.profdata | FileCheck %s -check-prefixes=V1,V2
+// RUN: llvm-cov show %t.exe -instr-profile=%t.profdata | FileCheck %s -check-prefixes=V1,V2
+
+// 4) Verify that coverage reporting on the aggregate coverage mapping shows
+//    hits for all code. (We used to arbitrarily pick a mapping from one binary
+//    and prefer it over others.) When only limited coverage information is
+//    available (just from one binary), don't try to guess any region counts.
+
+struct A {
+  A() {}    // V1: [[@LINE]]{{ *}}|{{ *}}1
+            // V1-ONLY: [[@LINE+1]]{{ *}}|{{ *}}|
+  A(int) {} // V2-ONLY: [[@LINE-2]]{{ *}}|{{ *}}|
+            // V2: [[@LINE-1]]{{ *}}|{{ *}}1
+};
+
+#ifdef _VERSION_1
+
+void foo();
+
+void bar() {
+  A x;      // V1: [[@LINE]]{{ *}}|{{ *}}1
+}
+
+int main() {
+  foo();    // V1: [[@LINE]]{{ *}}|{{ *}}1
+  bar();
+  return 0;
+}
+
+#endif // _VERSION_1
+
+#ifdef _VERSION_2
+
+void foo() {
+  A x{0};   // V2: [[@LINE]]{{ *}}|{{ *}}1
+}
+
+#endif // _VERSION_2